bsps/irq: Fix type limits warnings

Set BSP_INTERRUPT_VECTOR_COUNT to 1 to avoid type limits and array
bounds warnings.

Make sure all functions using the default interrupt controller
implementation return a status of RTEMS_UNSATISFIED.

Update #5298.
Close #5377.

bsps/include/bsp/irq-default.h

@@ -50,7 +50,7 @@ extern "C" {
  * By default, no interrupt vectors are supported and all related directives
  * return RTEMS_INVALID_ID.
  */
-#define BSP_INTERRUPT_VECTOR_COUNT 0
+#define BSP_INTERRUPT_VECTOR_COUNT 1
 
 /** @} */
 

bsps/include/bsp/irq-generic.h

@@ -68,12 +68,7 @@ extern "C" {
 #endif
 
 #ifndef BSP_INTERRUPT_DISPATCH_TABLE_SIZE
-  #if BSP_INTERRUPT_VECTOR_COUNT == 0
-    /* Avoid array subscript index is outside array bounds warnings */
-    #define BSP_INTERRUPT_DISPATCH_TABLE_SIZE 1
-  #else
-    #define BSP_INTERRUPT_DISPATCH_TABLE_SIZE BSP_INTERRUPT_VECTOR_COUNT
-  #endif
+  #define BSP_INTERRUPT_DISPATCH_TABLE_SIZE BSP_INTERRUPT_VECTOR_COUNT
 #endif
 
 #if !defined(BSP_IRQ_HAVE_GET_SET_AFFINITY) && defined(RTEMS_SMP)

bsps/shared/irq/irq-default.c

@@ -45,7 +45,7 @@ rtems_status_code bsp_interrupt_get_attributes(
   (void) vector;
   (void) attributes;
 
-  return RTEMS_SUCCESSFUL;
+  return RTEMS_UNSATISFIED;
 }
 
 rtems_status_code bsp_interrupt_is_pending(